Movable staybolt



Jan. 26, 1937.

J. URBANEK ET AL MOVABLE STAYBOLT Filed March 2, 1933 i Mm JUIUS Urban ek H s Helnzl IN VE NTDQ 5 6& M

Patented Jan. 26, 1937 UNITED STATES PATENT OFFICE MOVABLE STAYBOLT Application March 2,

1933, Serial No. 659,320

In Austria March 3, 1932 1 Claim.

The present invention relates to new and useful improvements in movable stay bolts.

Structures have heretofore been suggested in which two boiler walls are tightly connected with one another by means of a flexible tube, a stay bolt, usually a screw, being held free from flexure in the tube.

The usual practice has been to attach the tube to the boiler walls by beading or pressing. Such attachment often became loosened and, to increase its strength, the tube ends were shaped into cones in which conical fillers were inserted.

In accordance with the present invention, separately manufactured heads are attached to both ends of the tube. The tubes are fastened to the boiler walls by means of these heads, the latter being beaded or expanded by a mandrel.

Figs. 1-3 of the drawing exemplify three embodiments of the invention in longitudinal crosssection, corresponding parts in the various figures bearing the same reference numerals.

l is a bolt for transmitting traction forces. The bolt is supported free from flexure in spherical seats provided in a head and a nut. 2 is a flexible tube surrounding the bolt, and 3 and 4 are separately manufactured heads for the tube. 5 is the wall of the fire box and 6 the wall of the boiler.

In the arrangement shown in Fig. l, first the tube 2 is inserted through apertures provided in Walls 5 and 6. Then the heads 3 and 4 are inserted in the ends of the tube and are beaded over to hug the walls. Finally, the stay bolt l is inserted, preferably without subjecting it to preliminary tensioning.

In the arrangement shown in Fig. 2, the ends of tube 2 are fastened to walls 5 and 6 by flanging the heads 3 and 4. The head 3 has a flange or rim 8 which shields the bolt head against gases and thus prevents its corrosion.

In the embodiment illustrated in Fig. 3, the head 3 is extended beyond the wall 5 so that the head of the stay bolt I is seated to the right of this wall instead of to the left as shown in Figs. 1 and 2, more fully to protect the bolt head against gases. Here also connection with the Wall is established by rolling or beading the head 3.

In order to guard against rusting of the bolt head and nut on their seats, as shown in Fig. 2 thin, cup-shaped washers 9 of non-rusting material are provided.

We claim:

Stay bolt for steam boiler furnaces, comprising a flexible tube, a bolt mounted free of flexure in said tube, and separately formed heads provided at both ends of the said tube, each head having a shank portion projecting into the end of the tube and being provided with a flange embracing said tube end and being spread out and pressed against the boiler sheet through which the tube passes, whereby a tight connection is provided between the tube and the wall of the hole in the boiler sheet.

JULIUS URBANEK. HANS HEINZL. 

